When I get very nervous or worried I get this pain in the back of my neck, like someone is squeezing the cerebellum or something. It is quite uncomfortable and painful. It goes away as soon as I calm down. There is what seems to be an intense pressure in that spot where the neck meets the skull, that soft spot in the cannel above the back of the neck. What could it be? It is frustrating.

The first thing that came to my mind is tension headache with associated pericranial muscle tenderness. It would still be an atypical presentation but its the best I could think of. I think a good start would be to get a physical examination.